Electromagnetic relay



ELECTROMAGNETIC RELAY Filed March 29, 1950 x1. /j INVENTORS.

1 7716.97 6. in er: fiaZer? CfM'ereruZorf Patented Mar. 9, 1954ELECTROMAGNETIC RELAY Ernest G. Anger, Wauwatosa, and Robert C.

Mierendorf, Milwaukee, Wis.,

assignors to Square D Company, Detroit, Mich, a corporation of MichiganApplication March 29, 1950, Serial No. 152,594

12 Claims. 1

This invention relates to an electromagnetic relay and more particularlyto an electromagnetic relay which is especially designed to close anelectric circuit controlled by the relay with certainty and with nofaulty operation of the electric circuit occurring due to unwantedmomentary opening of the relay contacts immediately after closurethereof.

One object of the present invention is the provision of anelectromagnetic relay which is especially useful for triggering anassociated elec trical circuit and which comprises a bridging contactelement carrying a pair of movable contacts which cooperate with a pairof fixed contacts, the spacing between one of the fixed contacts and oneof the movable contacts being different from that between the other ofthe fixed contacts and the other of the movable contacts so as tonullify the effect of initial contact bounce.

Another object of the present invention is the provision of a relay inaccordance with the preceding objects and in which a core is magnetizedby an energizing coil and attracts a movable armature, the armaturehaving a movable interior member which prevents any momentary tendencyof the armature to move toward deenergized position immediately afterreaching the limit of the energized stroke.

Another object of the present invention is the provision of anelectromagnetic relay in accordance with the preceding objects in whichthe movable contacts are closed upon the fixed contacts in accordancewith the movement of an armature, the armature having an internal weightwhich operates to compress a spring as the armature reaches fullyenergized position, the spring transmitting its energy to the armatureto prevent its movement away from the core immediately upon reaching thefully energized position.

Other objects and features of the invention will be readily apparent tothose skilled in the art from the specification and appended drawingillustrating certain preferred embodiments in which:

Figure 1 is a front elevational view of the device of the presentinvention.

Figure 2 is an enlarged view around the lines III[ of Figure 1.

Figure 3 is a detailed sectional view along the lines III-I1I of Figure2.

The device of the present invention comprises a metallic mounting plateI provided with suitable apertures for firmly fixing the device to asurface, to which there is secured, as by welding, one leg of aninverted, generally U-shaped bracket member 2 which cooperates with anL- shaped bracket member 3 attached thereto by suitable studs 4 to mountan energizing coil 5 in position. The brackets 2 and 3 are of magneticmaterial to provide an exterior path for the magnetic flux. Theenergizing coil 5 has terminals e and 1 which may be connected in anenergizing circuit, while suspended from bracket 2 within the coil '5 isa core of magnetic material 8, which mounts a sleeve member 9 aboutwhich the energizing coil 5 is disposed. The core 8 has a centralopening through which extends an armature rod H for reciprocatorymotions therethrough.

Upon the lower end of the armature rod II, as viewed in Figure 2, ismounted an armature assembly generally designated by the numeral l2. Theexterior of the armature assembly [2 comprises an inverted, generallycup-shaped member I3 through which the armature rod ll projects. Abushing l4 and movable weight l5 are provided about a portion of thearmature rod II within the cup-shaped member [3. A washer I1 is providedto close the open end of the cup-shaped member [3, the washer l1 fittingagainst one end of the bushing i4 and clamping the member l3 on the rodll through the nut [8. A spring l6 about the bushing l4 and between thebase of member 12 and the weight l5 biases the weight against the washerI! in the normal position of the parts.

The upper end of the armature rod ll carries a movable contact assembly[9, studs 2| serving to clamp a base 22 of insulating material to theupper end of the armature rod II, the studs 2| cooperating with asuitable bracket 23 to accomplish this purpose. Mounted along the u peredge of the insulating base member 22 is a movable contact structureshown particularly in Figure 3, this structure consisting of a fixedouter enclosure of general U shape 24 having inwardly directed retainingflanges and which is fixedly secured to the base member 22. A spring 25is disposed within the U-shaped member 24 and supplies contact pressureby biasing a bridging contact element 26 away from the insulating base22, the ends of the bridging element 26 being provided with movablecontacts 21 and 28. Disposed in position to cooperate with the contacts21 and 28 are fixed contacts 29 and 30 mounted on insulating plate 33and having terminals 32 and 3| respectively, projecting through theplate for connection to the circuit to be controlled.

The fixed contacts are mounted at different distances from the undersurface of plate 33 as by the spacing washers 34 above contact 29 sothat the distance between the movable contacts 28 and the fixed contact30 is greater than the distance between the other movable contact 21 andthe fixed contact 28.

The operation of the device will now be described. When the energizingcoil 5 is deenergized, the armature and the contacts occupy the positionindicated by full lines in the Figure 2, the armature being fullyretracted away from the core member 8 and the movable contacts 2'! and28 occupying a position which is generally horizontal as viewed inFigure 2. When the energizing coil 5 is energized, the armature assemblyI2 is attracted toward the fixed core 8 and moves upwardly to decreasethe air gap therebetween. As the armature assembly approaches the fixedcore member 8, the contact 21 will first strike against the contact 29with animpact which may cause the contact 21 to rebound from the contact29, tilting the conducting bar 26 against the bias of the spring 25. Thespring 25, however, will cause the contacts 21 and 29 to rapidly recloseand to finish bouncing before contacts 28 and 38 engage to close thecircuit through the relay. When the electrical circuit connected betweenthe terminals 3| and 32 is one which requires an instantaneous pulse ofcurrent, it will be seen that the relay of the present invention willprovide just such pulse at the instant when the contact 28 closes uponfixed contact 30, as the rebound between the movable contact 21 and thefixed contact 23 has already occurred and these contacts are once againtogether. Consequently, in a circuit requiring just such a pulse, thecurrent will flow through the aforementioned electrical route betweenthe terminals 3 I and 32 and subsequent bounce between contacts!!! and30 will be of no consequence. It has been found that this type of relayis particularly effective in controlling the conduction of anignitronand prevents variation in firing due to erratic duration of bounce ofthe standard contact construction.

As the armature assembly i2 closes upon the core 8, the armature rod llcarries the base member l2 upward until the U-shaped member 24' is inposition indicated by dotted lines in Fig ure 2, in which case theconducting bar 26 is at an angle with respect to the horizontal asviewed in-F'igure 2, the spring 25 exerting a force upon the conductingbar 26 which tends to firmly hold the movable contact against the fixedcontacts.

If the energizing coil 5 should be located in an energizing circuitsubject to transient low voltage conditions, or in a circuit in which aresonating reactor is employed which would tend to reverse the directionof current flow through the energizing coil momentarily afterenergization of the coil 5, the armature i2 might tend to drop outimmediately after closing upon the core member 8. The relay of thepresent invention has, there fore, been provided with the movable weightl5 which acquires kinetic energy as the armature member I2 is movedtoward the core member 8 when the energizing coil 5 is energized, and atthe end of the upward stroke of the armature assembly I2 the movableweight dissipates this kinetic energy in the spring l5, resulting in aforce being exerted upon the inner surface of the cup-shaped member [3just following the instant at which the armature assembly reaches theupwardmost portion of its stroke. This upward thrust is exerted to aidin maintaining the contacts closed should any instantaneousdeenergization of the energizing core '5 tend to occur at this criticalinstant.

It will, therefore, be seen that the device of the present inventionprovides the particularly advantageous result of closing an associatedelectrical circuit with certainty and insuring that a controlledelectrical circuit receives a pulse of energy independent of any contactbounce or any momentary adverse conditions in the circuit controllingthe energizing coil employed. As has been earlier indicated, the deviceof the present invention has been found to be of particular advantage incontrolling the electrical circuit of ignitors. used tofire ignitrons,and especially in such a circuit where. a resonating reactor is employedin' series with the energizing coil, the movable weight as previouslydescribed overcoming the effect of the resonating reactor which mighttend to open the contacts by deenergization of the energizing coil justafter the armature has reached its fully operated position.

While certain preferred embodiments of the invention havebeenspecifically disclosed, it is understood that the invention is notlimited thereto, as many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims:

What is claimed is:

1. In an electromagnetic relay, fixed contacts, movable contactscooperating with said fixed contacts, an armature, an energizing coilfor effecting movement of said armature upon energization anddeenergization of said energizing coil, means connecting said armatureto said movable contacts, said armature comprising an outer en-.

closure having an internal spring and an internal Weight, said weightbeing movable relative to said outer enclosure and acting to compresssaid internal spring immediately after said armature reaches its fullyoperated position whereby the kinetic energy of said movable weight isutilized to prevent an immediate movement of said armature away from itsoperated position.

2. In an electromagnetic relay, fixed contacts, movable contactscooperating with said fixed contacts, an armature, an energizing coilfor effecting movement of said armature upon energization anddeenergization of said energizing coil, means connecting said armatureto said movable contacts, said armature comprising a cylindrical outermember having a spring and movable weight therein, said spring beinginterposed between said movable weight and the end of said cylindricalouter member nearest said movable contacts, said weight acting tocompress said internal spring immediately after said armature reachesits fully operated position whereby the kinetic energy of said movableweight is utilized to prevent an immediate movement of said armatureaway from its operated position.

3. In an electromagnetic relay, fixed contacts, movable contactscooperating with said fixed contacts, an armature, an elongated rodconnecting said armature to said movable contacts, an energizing coilfor eifecting movement of said armature upon energization anddeenergization of said energizing coil, said armature comprising anouter cylindrical shell having an internal spring and an internalmovable weight, said elongated rod extending into the interior of saidouter shell, said internal spring and weight being disposed about thesection of said elongated rod which extends into said cylindrical shelland guided thereby, the weight moving relative to said outer cylindricalshell and acting to compress said internal spring immediately after saidarmature reaches its fully operated position whereby the kinetic energyof said movable weight is utilized to prevent an immediate movement ofsaid armature away from its operated position.

4. In an electromagnetic relay, fixed contacts, movable contactscooperating with said fixed contacts, an armature member, an energizingcoil for effecting movement of said armature upon energization of saidenergizing coil, an elongated rod having one end connected to saidmovable contacts and one end to said armature member, said armaturemember including a bushing surrounding at least a section of said rod, aspring surrounding a first section of said bushing, a movable weightsurrounding a second section of said bushing, said second section beingcontiguous to said first section and further from the end of saidelongated rod connected to said movable contacts than said firstsection, and a hollow cylindrical shell surrounding said bushing, springand weight, one end of said spring abutting against an inner end surfaceof said cylindrical shell while the other end of said spring abutsagainst said movable weight, said movable weight being movable relativeto said cylindrical shell and acting to compress said internal springimmediately after said armature member reaches its fully operatedposition whereby the kinetic energy of said movable weight is utilizedto prevent an immediate movement of said armature away from its operatedposition.

5. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said coil, a bridging conductingmember having a pair of movable contacts thereon, means for moving saidmember and movable contacts in response to the movement of said armatureincluding a resilient mounting therefor, fixed contacts cooperating withsaid movable contacts, the open circuit gap between one of said fixedcontacts and one of said movable contacts normally being different thanthat between the other of said fixed contacts and the other of saidmovable contacts whereby said one of said movable contacts closes uponits 00- operating fixed contact before the other of said movablecontacts closes upon its associated fixed contact as said armature movesto fully operated position, said resilient mounting biasing the movablecontacts against the stationary contacts when closed, said armaturecomprising an outer enclosure having an internal spring and an internalweight, said weight being movable relative to said outer enclosure andacting to compress said internal spring immediately after said armaturereaches its fully operated position whereby the kinetic energy of saidmovable weight is utilized to prevent an immediate movement of saidarmature away from its operated position.

6. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said coil, a bridging conductingplate having spaced contacts thereupon, means for moving said conductingplate and contacts carried thereby in response to the movement of saidarmature, a bracket and a centrally disposed spring for normallypositioning said conducting plate in a predetermined plane, fixedcontacts for cooperating with the movable contacts, the distance betweenone of said fixed contacts and the movable contact with which itcooperates normally being different than the distance between the otherfixed contact and its cooperating movable contact so that said one setof contacts engages first as the armature moves toward closed position,said conducting plate moving out of said predetermined plane against thebias of said spring as said armature moves to fully operated positionupon energization of said energizing coil, said armature comprising anouter enclosure having an internal spring and an internal weight, saidweight being movable relative to said outer enclosure and acting tocompress said internal spring immediately after said armature reachesits fully operated position whereby the kinetic energy of said movableweight is utilized to prevent an immediate movement of said armatureaway from its operated position.

'7. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said energizing coil, a bridgingconducting member having a pair of movable contacts thereon, means formoving said member and movable contacts in response to the movement ofsaid armature including a re silient mounting therefor, fixed contactscooperating with said movable contacts, the open circuit gap between oneof said fixed contacts and one of said movable contacts normally beingdifferent than that between the other of said fixed contacts and theother of said movable contacts whereby said one of said movable contactscloses upon its cooperating fixed contact before the other of saidmovable contacts closes upon its associated fixed contact as saidarmatue moves to fully operated position, said resilient mountingbiasing the movable contacts against the stationary contacts whenclosed, said armature comprising a cylindrical outer member having aspring and movable weight therein, said spring being interposed betweensaid movable weight and the end of said cylindrical outer member nearestsaid movable contacts, said weight acting to compress said internalspring immediately after said armature reaches its fully operatedposition whereby the kinetic energy of said movable weight is utilizedto prevent an immediate movement of said armature away from its operatedposition.

8. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said coil, a bridging conductingplate having spaced contacts thereupon, means for moving said conductingplate and contacts carried thereby in response to the movement of saidarmature, a bracket and spring for normally positioning said conductingplate in a predetermined plane, fixed contacts for cooperating with saidspaced contacts, the distance between one of said fixed contacts and themovable contact with which it cooperates normally being different thanthe distance between the other fixed contact and its movable contact sothat said one set of contacts engages first as the armature moves towardclosed position, said conducting plate moving out of said predeterminedplane against the bias of said spring as said armature moves to fullyoperated position upon energization of said energizing coil, saidarmature comprising a cylindrical outer member having a spring andmovable weight therein, said spring being interposed between saidmovable weight and the end of said cylindrical member nearest saidmovable contacts, said weight acting to compress said internal springimmediately after said armature reaches its fully operated positionwhereby the kinetic energy of said movable weight is utilized to preventan immediate movement of said armature away from its operated position.

9. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said coil, a pair of fixed contacts,electrical conducting means for bridging the space between said fixedcontacts, said last mentioned means comprising a strip of conductingmaterial having a centrally disposed resilient mount, said fixedcontacts being spaced both laterally and in the direction of movement ofsaid movable contacts, means connecting said armature to said bridgingmeans whereby said bridging means is moved in response to the move mentof said armature, said bridging means moving into contact with saidfixed contacts against the bias of its resilient mounting as saidarmature moves to operated position upon energization of said energizingcoil, said armature comprising a cylindrical outer member having aspring and movable weight therein, said spring being interposed betweensaid movable weight and the end of said cylindrical member nearest saidmovable contacts, said weight acting to compress said internal springimmediately after said armature reaches its fully operated positionwhereby the kinetic energy of said movable weight is utilized to preventan immediate movement of said armature away from its operated position.

10. In an electromagnetic relay, an energizing coil, an armature memberadapted for recipro catory motion relative to said energizing coil uponenergization and deenergization of said coil, a bridging conductingmember having a pair of movable contacts thereon, means for moving saidmember and movable contacts in response to the movement of said armatureincluding a resilient mounting therefor, fixed contacts coopcrating withsaid movable contacts, the open circuit gap between one of said fixedcontacts and one of said movable contacts normally being different thanthat between the other of said fixed contacts and the other of saidmovable contacts whereby said one of said movable contacts closes uponits cooperating fixed contact before the other of said movable contactscloses upon its associated fixed contact as said armature member movesto fully operated position, said resilient mounting biasing the movablecontacts against the stationary contacts when closed, said means formoving said conducting plate comprising an elongated rod having one endconnected thereto and one end to said armature member, said armaturemember comprising a bushing surrounding at least a section of said rod,a spring surrounding a first section of said bushing, a movable weightsurrounding a second section of said bushing, said second section beingcontiguous to said first section and further from the end of saidelongated rod connected to said movable contacts than said firstsection, and a hollow cylindrical shell surrounding said bushing, springand weight, one end of said spring abutting against an inner end surfaceof said cylindrical shell While the other end of said spring weightbeing movable relative to said cylindrical shell and acting to compresssaid internal spring immediately after said armature reaches its fullyoperated position whereby the kinetic energy of said movable weight isutilized to prevent an immediate movement of said armature away from itsoperated position.

11. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said coil, a bridging conductingplate having spaced contacts thereupon, means for moving said conductingplate and contacts carried thereby in response to the movement of saidarmature, a bracket and spring for normally positioning said conductingplate. in a predetermined plane, fixed contacts for cooperating withsaid spaced contacts, the distance between one of said fixed contactsand the movable contact with which it cooperates normally beingdiiferent than the distance between the other fixed contact and itscooperating movable contact so that said one set of contacts engagesfirst as the armature moves toward closed position, said conductingplate moving out of its predetermined plane against the bias of saidspring as said armature moves to fully operated position uponenergization of said energizing coil, the mass of said conducting platebeing proportioned to the strength of said mounting spring and thedifierence in distances between one fixed contact and the other fixedcontact and their cooperating movable contacts so that reboundingmovement of the bridging means after engaging the first of said fixedcontacts has ceased when the second of the pair of fixed contacts isengaged by said bridging means, an armature comprising a cylindricalouter member having a spring and movable weight therein, said springbeing interposed between said movable weight and the end of saidcylindrical member nearest said movable contacts, said weight acting tocompress said internal spring immediately after said armature reachesits fully operated position whereby the kinetic energy of said movableweight is utilized to prevent an immediate movement of said armatureaway from its operated position.

12. In an electromagnetic relay, an energizing coil, an armature adaptedfor reciprocatory motion relative to said energizing coil uponenergization and deenergization of said coil, a pair of fixed contacts,electrical conducting means for bridging the space between said fixedcontacts, said last mentioned means comprising a strip of resilientlymounted conducting material, said fixed contacts being spaced bothlaterally and in the direction of movement of said movable contacts,means connecting said armature to said bridging means whereby saidbridging means is moved in response to movement of said armature, saidbridging means moving into contact with said fixed contacts against thebias of its resilient mounting as said armature moves to operatedposition upon energization of said energizing coil, the mass of saidbridging means being proportioned to the strength of the resilient mountof said bridging means and the displacement of said fixed contacts inthe direction of motion so that rebounding movement of the bridgingmeans after engaging the first of the pair of fixed contacts has ceasedwhen the second of the pair of fixed contacts is en aged by saidbridging means, an armature comprising a cylindrical outer mem-References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 20,094 Wilms et a1 Sept. 1, 1936 Number Number Name DateFerguson Sept. 26, 1911 Horton Mar. 5, 1912 Granberg June 4, 1940Borgkvist Apr. 15, 1941 Ayers et a1 Jan. 6, 1948 Austin July 19, 1949Shaw Nov. 15, 1949 Johnson Nov. 22, 1949 FOREIGN PATENTS Country DateGreat Britain Dec. 15, 1927

